Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> writes:
> On Tue, Oct 29, 2019 at 12:39 PM Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote:
>>
>> From: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
>>
>> Support storing and setting a pin path in struct bpf_map, which can be used
>> for automatic pinning. Also store the pin status so we can avoid attempts
>> to re-pin a map that has already been pinned (or reused from a previous
>> pinning).
>>
>> The behaviour of bpf_object__{un,}pin_maps() is changed so that if it is
>> called with a NULL path argument (which was previously illegal), it will
>> (un)pin only those maps that have a pin_path set.
>>
>> Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
>> ---
>
> Looks good, thanks! Just some minor things to fix up below.
>
> Acked-by: Andrii Nakryiko <andriin@xxxxxx>
>
>> tools/lib/bpf/libbpf.c | 164 +++++++++++++++++++++++++++++++++++-----------
>> tools/lib/bpf/libbpf.h | 8 ++
>> tools/lib/bpf/libbpf.map | 3 +
>> 3 files changed, 134 insertions(+), 41 deletions(-)
>>
>> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
>> index ce5ef3ddd263..fd11f6aeb32c 100644
>> --- a/tools/lib/bpf/libbpf.c
>> +++ b/tools/lib/bpf/libbpf.c
>> @@ -226,6 +226,8 @@ struct bpf_map {
>> void *priv;
>> bpf_map_clear_priv_t clear_priv;
>> enum libbpf_map_type libbpf_type;
>> + char *pin_path;
>> + bool pinned;
>> };
>>
>> struct bpf_secdata {
>> @@ -4025,47 +4027,119 @@ int bpf_map__pin(struct bpf_map *map, const char *path)
>> char *cp, errmsg[STRERR_BUFSIZE];
>> int err;
>>
>> - err = check_path(path);
>> - if (err)
>> - return err;
>> -
>> if (map == NULL) {
>> pr_warn("invalid map pointer\n");
>> return -EINVAL;
>> }
>>
>> - if (bpf_obj_pin(map->fd, path)) {
>> - cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
>> - pr_warn("failed to pin map: %s\n", cp);
>> - return -errno;
>> + if (map->pin_path) {
>> + if (path && strcmp(path, map->pin_path)) {
>> + pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
>> + bpf_map__name(map), map->pin_path, path);
>> + return -EINVAL;
>> + } else if (map->pinned) {
>> + pr_debug("map '%s' already pinned at '%s'; not re-pinning\n",
>> + bpf_map__name(map), map->pin_path);
>> + return 0;
>> + }
>
> `if (map->pinned)` check is the same in both branches, so I'd do it
> first, before this map->pin_path if/else.
But it's not. It's debug & return if pin_path is set, and an error
otherwise.
Will fix the rest of your nits :)
-Toke
